Species Composition and Community Characteristics of Typical Intertidal Shellfish in Qingdao, China

Abstract

The intertidal zone, a dynamic interface between the ocean and land, is one of the most diverse ecological habitats and harbors some of the richest biological communities. However, due to its unique location at the water's edge, it also bears the brunt of human activities in coastal areas. Intertidal biological resources serve as a foundation for the survival of coastal residents and plays a crucial role in coastal economic development. However, the intertidal zone serves as a primary area for coastal zone development and utilization, facing unprecedented environmental pressure resulting from rapid industrialization, urbanization, and agricultural intensification along coastlines. Consequently, safeguarding the intertidal ecological environment and biodiversity has become imperative for China's marine ecological civilization construction efforts. The coastal substrates in Qingdao encompass a diverse range of types, with predominantly rocky, sandy, and silt-muddy coasts constituting its coastline features. As an important marine center city encompassing coastal resorts and international port cities in China, Qingdao has witnessed rapid growth in its marine industry sector, while experiencing mounting pressure on its intertidal ecosystem. Shellfish are the predominant biological group in Qingdao's intertidal zone, exhibiting significant variation in species composition and community characteristics across different coastal types, thus serving as crucial ecological indicators for this zone. Despite a relatively early start to research on shellfish resources in Qingdao's intertidal zone, recent surveys focusing on shellfish distribution across various substrates are limited.To comprehensively assess the resource status and community structure of intertidal shellfish along the Qingdao coast, this study investigated intertidal shellfish resources at eight representative stations, including rocky, sandy, silt-muddy, and mixed sandy-rocky coastal types in May and October 2022. The composition of shellfish species, dominance patterns, and community structure parameters, including the Shannon-Wiener diversity index, Margalef richness index, and Pielou evenness index, were compared and analyzed at each station. Community clustering analyses were performed using similarity coefficient clustering and non-metric multi-dimensional scaling techniques. Our findings revealed in total 40 identified species of intertidal shellfish along the Qingdao coast. Among the stations surveyed for species richness, Canyon Street exhibited the highest number, with 18 species recorded, whereas Jinkou had the lowest, with only six species observed. The dominant species composition varied among survey stations and showed seasonal variations in type and dominance. During spring, Littorina brevicula, Mya arenaria, and Patelloida pygmaea emerged as the dominant species, whereas Crassostrea gigas, Musculista senhousia, and Ruditapes philippinarum dominated during fall. The Shannon-Wiener diversity index ranged from 0.85 to 1.84 and 0.66 to 2.00, Margalef richness index ranged from 0.86 to 1.97 and 0.62 to 2.96, and Pielou evenness index ranged from 0.41 to 0.84 and 0.31 to 0.98 in spring and autumn, respectively. Qiantaoyuan in Langya, Aoshanwei, and Cangkou exhibited the highest Shannon-Wiener diversity and Margalef richness indices among all stations. Community clustering results varied between spring and autumn at each station. Hongshiyi and Jinkou consistently formed separate branches, Cangkou and Wanggezhuang always clustered together, and the former Taoyuan in Langya and Aoshanwei were consistently grouped together. This study revealed that substrate type significantly influenced the composition and community structure characteristics of intertidal shellfish in Qingdao. This study identifies the status of shellfish resources on various substrates within Qingdao's intertidal zone, providing a foundation for resource development, protection, and ecological restoration efforts.

Keywords

• intertidal zone
• substrate
• community structure
• diversity
• dominant species